The CDC Advisory Committee on Immunization Practices (ACIP) has made specific recommendations regarding immunization for hepatitis A and B and whether to monitor response. Although these recommendations are summarized briefly below, MASAC strongly recommends that providers refer to the source documents referenced below, entitled "Prevention of hepatitis A through active or passive immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP)" and "Hepatitis B Virus: A comprehensive strategy for eliminating transmission in the United States through universal childhood vaccination: recommendations of the Immunization Practices Advisory Committee (ACIP)," for more specific details.

It is recommended that all individuals with bleeding disorders who are seronegative and unvaccinated should be immunized with hepatitis A vaccine after 2 years of age. This immunization is especially recommended for individuals who have hepatitis C infection.

Post-vaccine testing
Post-vaccination testing, although not indicated in general because of the high rate of vaccine response among adults and children, is strongly recommended for individuals with hemophilia.

Immunization with hepatitis B vaccine is recommended for all individuals with bleeding disorders who are seronegative and have not already been vaccinated.

Hepatitis B Post-vaccination Testing
Post-vaccination testing for serologic response is not recommended after routine vaccination of infants, children, or adolescents. Testing for immunity is advised only for persons whose subsequent clinical management depends on knowledge of their immune status (e.g., infants born to HBsAg-positive mothers, dialysis patients and staff, and persons with HIV infection). Individuals with hemophilia should also be evaluated for serologic response. Post-vaccination testing should also be considered for persons at occupational risk who may have exposures from injuries with sharp instruments, because knowledge of their antibody response will aid in determining appropriate post-exposure prophylaxis. When necessary, post-vaccination testing should be performed from 1 to 6 months after completion of the vaccine series.

Hepatitis B Vaccine Revaccination
Revaccination of nonresponders (i.e., those who do not respond to the primary vaccine series) is recommended. This is based on studies showing that 15-25% of nonresponders produce an adequate antibody response after one additional dose, and 30-50% after three additional doses. Therefore, vaccination with one or more additional doses should be considered for persons who do not respond to vaccination initially.

Hepatitis B Vaccine Booster Vaccination
For children and adults whose immune status is normal, booster doses of hepatitis B vaccine are not recommended, nor is serologic testing to assess antibody levels. Clinical trials of the hepatitis B vaccines licensed in the U.S. have shown them to be 80-90% effective in preventing hepatitis B infection and clinical hepatitis among susceptible children and adults. If a protective antibody response develops after vaccination, vaccine recipients are virtually 100% protected against clinical illness. The duration of immunity has been evaluated in long-term studies of both adults and children. Only the plasma-derived hepatitis B vaccines have been evaluated, as they have been in longest clinical use. However, on the basis of comparable immunogenicity and short-term efficacy, similar results would be expected with recombinant vaccines. The magnitude of the antibody response induced by the primary immunization declines over time. Among young adults (homosexual men and Alaskan Eskimos) who initially responded to a three-dose series, loss of detectable antibody has ranged from 13-60% after 9 years of follow-up. For children vaccinated after the first year of life, the rate of antibody decline has been lower than for adults. The peak antibody titers for infants are lower than for children immunized after 12 months of age, but the rate of antibody decline is comparable with that observed for adults in the same population. Long-term studies of healthy adults and children indicate that immunologic memory remains intact for at least 9 years and confers protection against chronic HBV infection, even though anti-HBs may become low or undetectable. In these studies, the HBV infections were detected by the presence of anti-HBc. No episodes of clinical hepatitis were reported, and HBsAg was not detected, although brief episodes of viremia may not have been detected because of infrequent testing. The mild, inapparent infections among persons who have been previously vaccinated should not produce the sequelae associated with chronic HBV infection and should provide lasting immunity. In general, follow-up studies of children vaccinated at birth to prevent perinatal HBV infection have shown that a continued high level of protection from chronic HBV infections persists for at least 5 years. As long-term data regarding re-boosting is not available, further studies will be needed to clarify this.

Persons with bleeding disorders such as hemophilia have an increased risk of acquiring hepatitis B and at least the same risk as the general population of acquiring other vaccine-preventable diseases. However, because of the risk of hematomas, intramuscular injections are often avoided among persons with bleeding disorders by using the subcutaneous route or intradermal routes for vaccines that are normally administered by the intramuscular route. Hepatitis B vaccine administered intramuscularly to 153 hemophiliacs using a 23-gauge needle, followed by steady pressure for 1 to 2 minutes, has resulted in a 4% bruising rate with no patients requiring factor supplementation. Whether an antigen such as pertussis that produces more local reaction would produce an equally low rate of bruising is unknown. When hepatitis B or any other intramuscular vaccine is indicated for a patient with a bleeding disorder, it should be administered intramuscularly if, in the opinion of a physician familiar with the patient's bleeding risk, the vaccine can be administered with reasonable safety by this route. If the patient receives anti-hemophilic or other similar therapy, intramuscular vaccination can be scheduled shortly after such therapy is administered. A fine needle (23 gauge) can be used for the vaccination and firm pressure applied to the site (without rubbing) for at least 2 minutes. The patient or family should be instructed concerning the risk of hematoma from the injection. Although several studies have shown efficacy and safety of vaccines, e.g. hepatitis A vaccine, given by the subcutaneous route, little information is available regarding long-term efficacy of non-intramuscular immunization. Further studies are needed to clarify this.

1. Centers for Disease Control and Prevention. Prevention of hepatitis A through active or passive immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1999;48(No. RR-12):1-37.
2. Centers for Disease Control and Prevention. Hepatitis B Virus: A comprehensive strategy for eliminating transmission in the United States through universal childhood vaccination: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1991;40(No. RR-13):1-19.

This material is provided for your general information only. NHF does not give medical advice or engage in the practice of medicine. NHF under no circumstances recommends particular treatment for specific individuals and in all cases recommends that you consult your physician or local treatment center before pursuing any course of treatment.

CHAPTERS: Please feel free to distribute to your members.
PHYSICIANS: Please distribute this information to all providers in your area who treat patients with bleeding disorders.